In recent years, organic solid polymer electrolytes have been extensively developed, which electrolytes have properties such as formability, a capability of being easily formed into a large area film, flexibility, and excellent adhesivity to electrodes, comparing with inorganic solid electrolytes.
Some polymers have been proposed in the form of organic solid polymer electrolytes. However, since for example, such polymers have been produced by electrolytic polymerization or a process requiring a long reaction time as disclosed in Japanese Patent Laid-Open Publication Nos. 4-171603 and 60-31555, the processes disclosed therein had a problem in productivity. The process disclosed in Japanese Patent Laid-Open Publication No. 2-298504 involves copolymerization of a precursor monomer and thus may encounter the shrinkage of the product caused by the polymerization, leading to a problem that it is difficult to produce such polymers easily from the industrial point of view.